Table 1 Exposure estimation methods used in this analysis and their spatial and temporal averaging scales
Exposure estimation methodTemporal averagingSpatial averaging
Personal measurements48 hIntegrated sample over all locations for the subject when the sample was collected
LUR: homeMonthly*, annualAverage for subjects’ home postal code location based on LUR (has about a 50 m spatial resolution)
LUR: home+workMonthly, annualTime-weighted average of home and work postal code locations based on LUR (has about a 50 m spatial resolution)
Ambient monitors (nearest monitor)Monthly, 48 h†Distance to nearest monitoring stations (about 10 km on average)
Ambient monitors (inverse distance weighting)Monthly, 48 h†Average of 3 nearest monitoring stations, weighted by distance – gives a spatial resolution that varies with monitor density
  • *No monthly averaging for absorbance; †ambient 48 h results not shown; described as sensitivity analysis in the Discussion.

  • LUR, land-use regression.